Three-ply temperature-regulating panel



9, 1966 J. 5. HICKMAN 3,265,121

THREEPLY TEMPERATURE-REGULATING PANEL Filed Dec. 10, 1963 2 Sheets-Sheet 1 a? I t /za 9 Ja/fnim'anm 1966 J. s. HICKMAN 3,265,121

THREE-FLY TEMPERATURE-REGULATING PANEL Filed Dec. 10, 1963 3 Sheets-Sheet 2 9 72 treni 01 J0%z ,5. Hiavauz f g [/2 (5 17 7/7 ,wacawwz dfiorrzgyzs United States Patent Office 3,265,121 Patented August 9, 1966 3,265,121 THREE-PLY TEMPERATURE-REGULATING PANEL John S. Hickman, Shorewood, Wis., assignor to Inland Steel Products Company, Milwaukee, Wis., a corporation of Delaware Filed Dec. 10, 1963, Ser. No. 329,410

19 Claims. (Cl. 165-49) The present invention relates generally to wall or ceiling panels used in rooms of commercial and institutional buildings for temperature-regulating purposes, and more particularly to a three-ply panel including prefabricated elongated tube-like passages for conducting a temperature-regulating fluid.

Essentially, a panel constructed in accordance with the present invention includes three superimposed plies or layers with a middle ply in facing relation with and bonded between two outside plies. That outside ply which is to be exposed to the interior of the room is perforated along the entire area thereof. These perforations provide sound-proofing characteristics to the panel, help mask distortions and ghost lines from the other two plies, and provide an aesthetic effect. The middle ply and the other outside ply, not exposed to view from the interior of the room, each include an elongated deformed portion, both of which cooperate to define an elongated tube-like passage for conducting a temperature-regulating fluid, such as hot or cold water. The fluid employed depends upon the temperature conditions in the particular room.

The undeformed portions of the middle ply and other outer ply are perforated with openings in axial alignment with corresponding openings on the first outer ply, i.e. the ply facing the interior of the room. All these perforations contribute to the provision of sound-proofing characteristics.

The deformed portion of the middle ply is spaced substantially from the closest portion of the outer ply facing the interior of the room. This spacing is substantial enough, and the perforations in the first outer ply are small enough, to prevent the deformed portion of the middle ply from being viewed by an observer of the panel standing in the room. Because the deformed portion of the middle ply is not capable of being viewed from the interior of the room, the middle ply need not be constructed of material heavy enough to withstand the distortion to which the deformed portion is subjected during hydraulic testing of the tubular passage through which the temperature-regulating fluid passes. Because the distortion does not interfere with the functional characteristics of the tubular passages, a lighter gauge material for the middle ply can be tolerated, with a substantial saving for material, when a large number of panels are being fabricated.

Because the first outer ply is perforated along the en tire area thereof, all ghost lines and distortions on the middle and other outer ply, whether caused by the bonding of the plies or whether previously present, are masked, Without such perforations, it would appear to an observer in the room looking at a panel that there are lines (ghost lines) corresponding, in outline, to the path followed by the fluid-confining passages defined by the deformed portions of the intermediate and other outer ply,

Because the first outer ply is spaced substantially from the closest part of the deformed portion of the middle ply and does not define any part of the tubular passage for the temperature-regulating fluid, the entire area of the first outer ply can be perforated. This would not be the case if the first outer ply included a portion defining part of the fluid-confining passage.

Furthermore, because the first outer ply does not constitute a part of the fluid-confining passage, it need not be heavy enough to resist distortion arising as a result of hydraulic testing of the fluid-confining passage. Accordingly, the first outer ply, the only ply viewed by one standing in the room, may be relatively thin, thus resulting in a substantial saving on a large number of panels.

Moreover, because the first outer ply is completely covered with perforations, any blemishes on that surface of the first outer ply facing the interior of the room are more fully masked than would be the case if there were unperforated portions on the first outer layer.

Other features and advantages are apparent in the structure claimed and disclosed or will become apparent to those skilled in the art from the following detailed description in conjunction with the accompanying diagram matic drawings wherein:

FIGURE 1 is a fragmentary perspective view, as seen from above, partially in section and partially in phantom, illustrating an embodiment of a three-ply temperature regulating panel, constructed in accordance with the pres ent invention, and including a light troffer housing;

FIGURE 2 is a fragmentary perspective view, partially in section, illustrating the embodiment of the panel of FIGURE 1, as seen from below;

FIGURE 3 is an enlarged fragmentary perspective view of a portion of an embodiment of a three-ply temperature-regulating panel constructed in accordance with the present invention;

FIGURE 4 is a fragmentary perspective view, partially in section, illustrating an embodiment of :a panel, constructed in accordance with the present invention, and associated with structure for supporting said panel as part of a room ceiling;

FIGURE 5 is an enlarged fragmentary sectional view illustrating another embodiment of a three-ply radiant panel, constructed in accordance with the present invention, and including a light trolfer housing;

FIGURE 6 is a schematic drawing of an embodiment of a panel, constructed in accordance with the present invention, including a light troffer housing and intended for use along the periphery of the interior of a building; and

FIGURE 7 is a fragmentary sectional view of still an other embodiment of a three-ply panel, constructed in accordance with the present invention.

. Referring initially to FIGURE 3, there is illustrated an embodiment 10 of a three-ply temperature-regulating panel constructed in accordance with the present invention. Panel 10 includes a middle ply 11, a first outer ply 12, and another outer ply 13. The three piles are typically composed of metallic material, such as galvanized steel; the middleply 11 is bonded to first outer ply 12 by means such as brazing at 21; and middle ply 11 is bonded to other outer ply 13 by means such as brazing at 22.

Middle ply 11 includes a deformed portion 14, and outer ply 13 includes a deformed portion 15. Deformed portions 14 and 15 cooperate to define a fluid-confining passage 16 having a tubular cross-section.

Deformed portion 14 on middle ply 11 is, in the embodiment of FIGURE 3, composed of three parts, 17, 18 and 19. For the most part, all of deformed portion 14 is spaced substantially from the closest part 20 of first outer ply 12. Middle ply 11 and outer ply 13 each include undeformed portions, 23 and 24, respectively. Middle ply 11 has one surface 28 in facing relation to a surface 29 on first outer ply 12; and middle ply 11 has another surface 30 in facing relation to a surface 31 on other outer ply 13. Middle ply surface 28 is in substantially contacting engagement with surface 29 on outer ply 12 along substantially the entirety of the undeformed portion 23 of middle ply 11. Similarly, surface 30 on middle ply 11 is in substantially contacting engagement with the surface 31 on other outer ply 13 along substantially the entire area of the undeformed portions 23, 24 of plies 11 and 13.

Outer ply 12 includes a plurality of perforations regularly spaced, in the embodiment of FIGURE 3, along substantially the entire area of outer ply 12. Middle ply 11 includes a plurality of perforations 26 along substantially the entire area of the middle plys undeformed portion 23. Similarly, the other outer ply 13 includes a plurality of perforations 27 along substantially the entire area of undeformed portion 24 of outer ply 13. Each perforation 26 is axially aligned with a perforation 25. in first outer layer 12; and each perforation 27 is axially aligned with corresponding perforations 25, 26 in outer and middle layers 12, 11 respectively. Deformed portions 14, 15 of plies 11 and 13, respectively, are imperforate.

In panel 10, the undeformed portions, 23, 24 of middle and outer plies 11 and 13, respectively, have contours corresponding to the flat contour of outer ply 12.

Outer ply 12 is that ply of panel which is exposed to view when the panel defines a part of the wall or ceiling of a room. Because the entirety of outer ply 12 is perforated, ply 12 masks from view all distortions, imperfections, blemishes and ghost lines which may be present in plies 11 and 13. In addition, perforations 25 in ply 12 effectively mask any blemishes, etc., in ply 12.

The spacing between deformed portion 14 of middle ply 11 and outer ply 12s closest facing part 20 is sufiiciently great, and the size of openings 25 in outer ply 12 is sufiiciently small, so that deformed portion 14 of middle ply 11 is not capable of being viewed through openings 25. Because deformed portion 14 is not subject to being viewed, it may be constructed of a material lighter than that which will resist distortion arising as a result of hydraulic testing of tubular passages 16, so long as panel 11 is constructed of material heavy enough to prevent bursting or leakage during such hydraulic testing. In a typical embodiment, constructed to withstand a hydraulic testing of 150 p.s.i., middle panel 11 may be constructed of 22 gauge steel.

Because outer ply 12 does not constitute any part of a fluid-confining passage and is not subject to distortion by hydraulic testing, outer ply 12 may be constructed of very light material, even lighter than the material used for middle ply 11. In one embodiment, outer ply 12 need only be of veneer thickness, and can be bonded to middle ply 11 by means such as glue or other adhesive, bonding by brazing being eliminated entirely.

Furthermore, because outer layer 12 does not constitute any portion of a fluid-confining passage, the entire area thereof may be perforated. As previously indicated, the deformed portions 14, of plies 11 and 13 respectively, are imperforate because they define a fluid-confining passage.

A typical sequence of operations for fabricating panel 10 includes forming plies 11 and 13, perforating ply 12 only, bonding plies 11, 12 and 13 together simultaneously (e.g. by hydrogen brazing using conventional brazing material such as copper), perforating plies 11 and 13 using the perforations in ply 12 as guides and then painting or otherwise finishing.

Referring now to FIGURE 7, there is illustrated another embodiment of a three-ply temperature-regulating panel constructed in accordance with the present invention. Panel 110 includes a middle ply 111, a first outer 4 ply 112 and another outer ply 113. Middle and outer plies 111, 113 include respective deformed portions 114, 115 cooperating to define a fluid-confining passage 116 of tubular cross-section.

Middle ply 111 includes an undeformed portion 123 having contours conforming to the flat contour of outer ply 112. Middle ply 111 has a surface 128, a substantial part of which faces a surface 129 on outer ply 112; and middle ply surface 128 is in contacting engagement with outer ply 112s surface 129 along substantially the entire area of undeformed portions 123 on middle ply 111.

Deformed portion 114 on middle ply 111 is spaced a relatively substantial distance from outer ply 112, for the most part; and deformed portion 114 includesintegrally .serially connected parts 117, 132, 118, 133,and 119.

The other outer layer 113 includes portions 124 spaced substantially from undeformed portion 123 on middle ply 111. Deformed portion 115 of outer play 113 includes integrally serially connected parts 137, 134, 135, 136 and 138. Ply 113 includes a surface 131 facing the other surface 130 of middle ply 111; and surface 130 on ply 113 is in contacting engagement with surface 130 on middle ply 111 along parts 134 and 132 and parts 136 and 133 of plies 113, 111, respectively.

Parts of middle ply 111 and parts of outer ply 113 cooperate to define a housing containing a soundproofing, fireproofing material 139 (e.g. mineral wool acoustical batting capable of resisting temperatures up to 2500 F.). This housing is defined by parts 119, 123, and 117 of middle ply 111, and parts 138, 124, and 137 of outer ply 113. Another housing for material 139 is defined by first outer ply 112 and by parts 117, 132, 118, 133 and 119 of middle ply 111.

In embodiment 110 first outer ply 112 includes a plurality of perforations 125, similar to perforation 25 in ply 12 of embodiment 10. The undeformed portion 123 of middle ply 111 includes a plurality of perforations or openings 126, each axially aligned with a corresponding perforation in outer ply 112. However, in this embodiment (110), the perforations 126 have a larger diameter than the openings 125 in outer ply 112. Openings 126 are made larger than openings 125 to provide a more uniform appearance, and to permit prepunching of all the openings in both plies 111 and 112 without previous precision alignment.

Ply 111 may be bonded to ply 112 and to ply 113 with bonding media similar to that with which ply 11 was bonded to plies 12 and 13 in embodiment 10 of FIG- URE 3.

Embodiment 110 includes other advantages over embodiment 10 of FIGURE 3. For example, plies 111 and 113 may be more readily aligned for good brazing; ply 113 is completely imperforate thereby preventing sound transmission outwardly through one panel and then inwardly through another panel in another room; the entire assembly of plies 1'11, 112 and 113 can be brazed upside down (with ply 112 on top) so that any fluid brazing which may run through and puddle on ply 112 does so on the unexposed, unseen surface 129 of ply 112, thus avoiding an unsightly surface finish on ply 112; and plies 111, 112 are identical (though inverted each relative to the other) and can be made on the same dies, thereby affording a substantial savings in the preparation of dies.

Referring now to FIGURES 1 and 2, there is illustrated a three-ply radiant panel 10, a part of which has been further deformed to define a light troffer or housing indicated generally at 50. Trotfer 50 is composed of plies 11 and 13, with outer ply 12 having an opening 51 constituting a trofier opening defined by rim portion 52 on outer ply 11. Integral with rim portion 52 is an upstanding flange portion 53 extending around the entirety of opening 51.

Trotfer 50 includes a top 55, sides 56, 57 and ends 58, 59. Tubular passages 16 on panel 10continue up the sides 58, 59 of trotfer 50, and cross the top 55 thereof.

The tubular passage portions extending across troffer 50 are indicated by numeral 215 in FIGURES 1 and 2. Also formed as a part of trofier 50 are tubular passage portions 216 extending around the troffer ends 56, 57. Tubular portions 215, 216 on troifer 50 may be formed in the same manner as previously described tubular passages 16 on panel 10.

Referring to that portion of panel illusrated in FIG- URE 1, temperature-regulating fluid enters tubular pas- I sage 16 at 60, runs through the tubular passages 16, 215

and 216, and exits from panel 10 at 61. In this embodiment, the same temperature-regulating fluid passes through the tubular passages 215, 216 as passes through the tubular passages 16.

In the embodiment illustrated diagrammatically in FIGURE 6, a different temperature-regulating fluid passes through the trofi'er tubular passages 215, 216 than that which passes through the panel tubular passages 16. More specifically, the temperature-regulating fluid for the panel tubular passages 16 enters panel 10 at 160' and exit at 161 without having passed over, around or along trofler 50. A second temperature-regulating fluid enters the tubular passages 216 at 170, continues through tubular passages 215, and leaves troifer 50 and panel 10 at 171. A flow arrangement of the type illustrated diagrammatically in FIGURE 6 would be used in conjunction with a panel located along the periphery of the interior of a building. Thi is because, in cold weather, the temperature-regulating fluid passing through tubular passages 16 would be at elevated temperatures to provide heating at the periphery of the building, whereas the temperature-regulating fluid passing through the passages 215, 216 on troifer 50 would have a relatively low temperature to provide cooling for the trolfer housing to offset the heat generated by the lights located within the tr-offer housing.

Referring now to FIGURE 5, there is illustrated another embodiment of radiant panel including a light troffer 50. A main difference between this embodiment and the embodiment illustrated in FIGURES 1 and 2 is that the tubular passages 316-in the embodiment of FIGURE 5 have a round cross-section rather than being triangular like those in the embodiment of FIGURES 1 and 2. In FIGURE 5, the phantom lines illustrate a trofier frame 62 supported by the troifer opening edge portion 52 of outer ply 12.

Referring now to FIGURE 4, there is illustrated a arrangement wherein a three-ply temperature-regulating panel 10 forms a part of the ceiling in a room and is supported by structural member of the building in which the room is included. More specifically, each of the plies in the panel includes a peripheral web portion 71, 72, 73, and an outwardly extending flange portion 81, 82, 83 for each of the three plies 11, 12 and 13, respectively. Flange portions 81, 82, 83 are supported by a member 74 constituting an aluminum ceiling and partition track. Atop panel 12 is a layer 77 of fireproofing and soundproofing material (e.g., fiberglass). Applied over layer 77 and over member 74 is a layer of castable material such as concrete or the like. As used herein the term castable means a material which may be poured or sprayed or otherwise applied in fluid form, and which then hardens to a permanent, non-fluid condition. The castable material 76 is reinforced by wire mesh 78, having an end portion 79 attached to the outer peripheral edge portion of the panel at the flanges 81, 82, 83. If desired, castable material 76 may be reinforced with a member 75 typically constituting a steel bulb T.

Among the advantages of the arrangement shown in FIGURE 4 is: if there should be a fire in the interior of the room, and if the fire melts the aluminum partition track member 74, the layer of castable material 76 overlying member 74 would still be supported by member 75. By the same token, if fire should cause the melting or 6 sagging of panel 10, the reinforcing mesh 78 would still support the castable material 76 by virtue of the ends of mesh 78 being attached to the peripheral portions 81, 82, 83 themselves sufficiently embedded in the layer of castable material 76 to prevent their being melted by fire.

There have thus been described typical embodiments of three-ply temperature-regulating panel including tubular passages for the transmission of a temperature-regulating fluid.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.

What is claimed is:

1. A three-ply temperature-regulating panel comprising:

a first outer ply;

a middle ply;

another outer ply;

means bonding said middle ply to said first outer ply with the two plies in facing relation;

means bonding said middle ply to said other outer ply with the two plies in facing relation;

an elongated, deformed portion on each of said middle and other outer plies;

said deformed portions cooperating to define a fluidconfining passage;

said deformed portion of the middle ply being substantially spaced from the closest facing part of the first outer ply;

a plurality of perforations along the entirety of said first outer ply;

a plurality of perforations in the undeformed portion of at least said middle ply;

each perforation in the middle ply being aligned with a perforation in the first outer ply;

the deformed portions of said middle and other outer ply being imperforate.

2. A three-ply temperature-regulating panel having an integral elongated fluid-confining passage of tubular crosssection, said panel comprising:

a first ply of predetermined contour;

a second ply in facing relation with said first ply;

said second ply including a portion having a predetermined contour corresponding to said predetermined contour of the first ply, and an elongated deformed portion having a lateral cross-section defining part of the tubular cross-section of a fluid-confining passage;

a third ply in facing relation with said second ply;

said third ply including a portion having a predetermined -contour corresponding to said predetermined contour of said first recited portion on the second ply, and an elongated deformed portion having a lateral cross-section defining the rest of said tubular cross-section of said fluid-confining passage;

sa-id first recited portion of said second ply being in substantially contacting engagement with said first ply along the entirety of said second plys first recited portion; said deformed portion of the second ply being spaced substantially from said first ply along substantially the entirety of said second plys deformed portion said first recited portion of the third ply being in substantially contacting engagement with said first recited portion of said second ply along the entirety of said first recited portion of the third ply;

said deformed portions on said second and third plies cooperating to define an elongated, fluid-confining passage of tubular cross-section for said panel; means bonding said second ply to said first ply;

means bonding said third ply to said second ply;

perforations across the entire area of said first ply;

perforations in the first recited portion of said second ply with each of said perforations being in alignment with a respective perforation in the first ply;

and perforations in the first recited portion of said third ply with each of said perforations being in alignment with a respective perforation in the second ply;

the deformed portions of said second and third plies being imperforate.

3. A three-ply temperature-regulating panel as recited in claim 2 wherein:

each perforation in that part of the first ply which is in contacting engagement with the first recited portion of the second ply is axially aligned with a respective perforation in said first recited portion of the second ply;

and each perforation in the second ply is axially aligned with a respective perforation in the first recited portion of the third ply.

4. A three-ply temperature-regulating panel as recited in claim 2 wherein:

said first ply is fiat, and the first recited portions of said second and third plies are fiat and substantially undeformed.

5. A three-ply temperature-regulating panel as recited in claim 2 wherein:

said perforations in the first ply are sufficiently small,

and said one surface on the deformed portion of said second ply is spaced sufiiciently from the facing surface of said first ply to prevent said second ply from being visible through the perforations in the first ply.

6. A three-ply temperature-regulating panel as recited in claim 2 wherein said first ply is thinner than either of the other two plies.

7. A three-ply temperature-regulating panel as recited in claim 2 wherein said second ply is thinner than the thickness required to resist distortion from the hydraulic pressure at which said panel is tested for leaks.

8. A three-ply temperature-regulating panel as recited in claim 7 wherein said second ply is thinner than the thickness required to resist distortion from hydraulic pressure of 150 psi.

9. A three-ply temperature-regulating panel as recited in claim 7 wherein said first ply is thinner than said second ply.

10. A three-ply temperature-regulating panel as recited in claim 9 wherein said first ply is bonded to said second ply with adhesive.

11. A three-ply temperature-regulating panel as recited in claim 2 wherein:

all of said plies are composed of metallic material;

and at least said second and third plies are bonded together by brazing.

12. A three-ply temperature-regulating panel as recited in claim 2 and comprising:

a relatively large opening in said first ply, and constituting a troifer opening;

said first ply including a rim portion defining said opening and including means for mounting a trotfer frame;

said second ply including a relatively large deformed part defining the interior layer of a two-ply trofler housing;

said third ply including a relatively large deformed part defining the exterior layer of a two-ply trolfer housing;

said interior layer including a portion having a predetermined contour and an elongated further deformed portion having a lateral cross-section defining part of the tubular cross-section of a fluid-confining passage;

said exterior layer including a portion having a predetermined contour corresponding to the contour of said first recited portion on the inner layer and an elongated further deformed portion having a lateral cross-section defining the rest of said tubular crosssection of said last recited fluid-confining passage; the first recited portions of said inner and outer layer having facing surfaces at least parts of which are in substantially contacting engagement;

the further deformed portions of said inner and outer layers cooperating to define a fluid-confining passage of tubular cross-section for said troffer.

13. A three-ply temperature-regulating panel as recited in claim 12 and comprising:

a first inlet means for connecting said fluid confining passage for the panel to a source of fluid;

and second inlet means for said troffer housing fluid confining passage for connecting the latter passage to a fluid source other than said first recited fluid source.

14. In combination with the three-ply temperatureregulating panel of claim 2:

means, including structural members, engaging peripheral edge portions of said panel for supporting said panel in an elevated horizontal disposition;

an intermediate layer of fireproofing, soundproofing material atop said third ply;

an upper layer of cast fireproofing material atop said intermediate layer;

and reinforcing means embedded in said upper layer and connected to said supporting means for support of said reinforcing means in the event said three-ply temperature-regulating panel should give way in a fire.

15. A three-ply temperature-regulating panel having an integral elongated fluid-confining passage of tubular cross-section, said panel comprising:

a first ply of predetermined contour;

a second ply in facing relation with said first ply;

said second ply including a portion having a predetermined contour corresponding to said predetermined contour of the first ply and an elongated deformed portion having a lateral cross-section defining part of the tubular cross-section of a fluid-confining passage;

a third ply in facing relation with said second ply;

said third ply including an elongated deformed portion having a lateral cross-section defining the rest of said tubular cross-section of said fluid-confining passage;

said first recited portion of said second ply being in substantially contacting engagement with said first ply along the entirety of said second plys first recited portion;

said deformed portion of the second ply being spaced substantially from the closest facing part of said first ply along substantially the entirety of said second plys deformed portion;

part of said third ply being in substantially contacting engagement with part of said second ply;

said deformed portions on said second and third plies cooperating to define an elongated, fluid-confining passage of tubular cross-section;

means bonding said second ply to said first ply;

means bonding said third ply to said second ply;

perforations across the entire area of said first ply;

perforations in the first recited portion of said second ply, with each of said perforations being in alignment with a respective perforation in the first ply;

the deformed portions of said second and third plies being imperforate.

16. A three-ply temperature-regulating panel as recited in claim 15 wherein:

the perforations in said second ply are larger in area than the perforations in said first ply.

17. A three-ply temperature-regulating panel as recited in claim 16 wherein:

said third ply includes a portion in facing relation with and spaced substantially from said perforated first recited portion of the second ply.

13. A three-ply temperature-regulating panel as recited in claim 17 wherein:

UNITED STATES PATENTS 2,677,749 5/1954 Raider 165--56 X 10 Jorn 16556 X Wolf 165136 X Baran 165-57 X Reynolds 165-170 X Shippee et a1 16549 X Werden 16556 X FOREIGN PATENTS France.

10 ROBERT A. OLEARY, Primary Examiner.

A. W. DAVIS, Assistant Examiner. 

1. A THREE-PLY TEMPERATURE-REGULATING PANEL COMPRISING: A FIRST OUTER PLY; A MIDDLE PLY; ANOTHER OUTER PLY; MEANS BONDING SAID MIDDLE PLY TO SAID FIRST OUTER PLY WITH THE TWO PLIES IN FACING RELATION; MEANS BONDING SAID MIDDLE PLY TO SAID OTHER OUTER PLY WITH THE TWO PLIES IN FACING RELATION; AN ELONGATED, DEFORMED PORTION ON EACH OF SAID MIDDLE AND OTHER OUTER PLIES; SAID DEFORMED PORTIONS COOPERATING TO DEFINE A FLUIDCONFINING PASSAGE; SAID DEFORMED PORTION OF THE MIDDLE PLY BEING SUBSTANTIALLY SPACED FROM THE CLOSET FACING PART OF THE FIRST OUTER PLY; A PLURALITY OF PERFORATIONS IN THE ENTIRETY OF SAID FIRST OUTER PLY; A PLURALITY OF PERFORATIONS IN THE UNDEFORMED PORTION OF AT LEAST SAID MIDDLE PLY; EACH PORFORATION IN THE MIDDLE PLY BEING ALIGNED WITH A PERFORATION IN THE FIRST OUTER PLY; THE DEFORMED PORTIONS OF SAID MIDDLE AND OTHER OUTER PLY BEING IMPERFORATE. 